Method of constructing a continuous tube finned heat exchanger



W. A. COLLINS 3,440,704

Shee'I Z of 4 duf o La :5 w W9- 9 i N 9 m i MM- wW/\\w\\.\% www 99 Mn.1.- 59W mmv l t 99.19 m9 UW Mm w\\\mm 5N April 29, 1969 METHOD OFCONSTRUCTINC- A CONTINUOUS TUBE FINNED HEAT EXCHANGER Filed DeC. 26,1967 \N\\\ NW N mw l f l Ww?! ww I. NEW ww@ 9 V, d M9999 Q -1U @@mwxw Hlnvum. RQ

April 29, 1969 w. A. coLLlNs 3,440,704

METHOD OF CONSTRUCTING A CONTINUOUS TUBE FINNED HEAT EXCHANGER FiledDec. 26, 1957 sheet 2, of 4 April 29, l969v w. A. coLLlNs 3,440,704

METHOD OF CONSTRUCTING A CONTINUOUS TUBE FNNED HEAT EXCHANGER Filed Dec.26, 1967 sheet 3 of 7 i4 i! j; j; jf v f/ f4 if Z /W f/A 4/0 I y j; 7fw! y y; 7 74 /M f4 W M 7X5 {H f4 E- f5 if l N VENTOR.

April 29, 1969 w. A. cOLLlNS 3,440,704

METHGD OF CONSTRUCTING A CONTINUOUS TUBE FNNED HEAT EXCHANGER Filed Deo.2s, 1967 snee; 4 of 4 j; /f fa United States Patent O U.S. Cl. 29157.310 Claims ABSTRACT OF THE DISCLOSURE The method pertains to thethreading of a continuous tube of conducting material back and forththrough a stack of ns having a plurality of apertures which are inaligned relation to form a plurality of through openings. The tube isinserted through the first open-ing, reversed, advanced and pulledthrough the second opening forming a loop. The tube is again reversedand advanced and pulled through a third opening forming another loop andso on until all of the openings have straight tube sections extendingtherethrough with opp'ositely disposed loops on the ends forming acontinuous sinuous tubul-ar path. The loops are either dr-awn toward thetins or the ins yare moved apart towards the l-oops.

Background of the invention There was no art uncovered which disclosedthe method of so threading a continuous tube through a plurality ofopenings formed by aligned apertures in the tins.

Summary of the invention The stacked fins and end elements with theapertures aligned forming a plurality of through openings are placed ina tray which is periodically advanced to align the openings seriatimalong the center of the machine where the tube is pushed and pulledthrough the openings to form loops on the ends. Similar devices areemployed on opposite ends of the machine to push and pull the tubethrough an opening on the center of the devices. The pulling device ismoved a substantial distance because of the substantial length of thetube when drawn through the -first opening. The distance the pullingdevices must move can be substantially shortened by inserting the tubeat the center of the stack of fins and end elements and thread the tubethrough the opening toward one side after which the stack can be turnedover so that the other end of the inserted tube can be threaded throughthe openings on the other side of the stack with all of the threading-occurring on the center line of the machine. A reversing device isprovided between the pulling device and the tins which is movedoutwardly with the pulling device and spaced a predetermined distancetherefrom so that a predetermined length of tube can be reversed. Thereversing device is in position to grasp the tube as it is released fromthe pulling device and bend the tube about a mandrel forming a largeloop when reversing the end length. The length is located on the machinecenter line so that when a stack of tins is indexed to locate the nextadjacent opening on the center line, the return movemen-t of the pullingdevice picks up the reversing device and moves the tube toward andthrough the opening a suflicient distance to have the free end inposition to be engaged by the pulling device on the opposite side of thelin stack. rl`he reversing device is unclamped and 3,440,704 PatentedApr. 29, 1969 clamping and lowered to permit the tube to be formed intoan end loop.

In this manner the tube is threaded through the openings of the stack tohave straight portions extending through the ns with oppositely disposedloops on the ends. The loops are either drawn close to the tins or theiins are spread apar't to engage the loops after which pressure isprovided within the tube to cause the expansion thereof and to provide a360 cont-act with the edge of the apertures through the tins and endelements. The ends of the tubes are cut off to provide short sections,when the tube is made of aluminum or like material which is diicult tobraze or otherwise attach to the conduits of a heat exchange system, anda short section of copper tube attached thereto.

Brief description of the drawings rFIGURE 1 is a broken plan view of amachine for practicing the method of the present invention;

FIG. 2 is a side view of the machine illustrated in FIG. 1;

FIG. 3 is an enlarged sectional view of the structure illustrated inFIG. 2, taken on the line 3 3 thereof;

FIG. 4 is an enlarged sectional view o-f the structure illustrated inFIG. 2, taken on the line '4 4 thereof;

FIG. 5 is an en enlarged sectional view of the structure illustrated inFIG. 2, ta'ken on the line 5 '5 thereof;

FIG. 6 is an enlarged broken view of the structure illustrated in FIG.l, showing the end section of the tube reversed;

FIG. 7 is an enlarged broken sectional view of the structure illustratedin FIG. 2, taken on the line 7-7 thereof;

FIG. 8 is an enlarged broken sectional view of a portion of thestructure illustrated in FIG. 6,4taken on the line 8-'8 thereof;

FIG. 9 is a view of loop forming lstructure, similar to -thatillustrated in FIG. 1, showing another form of the invention;

FIG. l0 is -a view of structure, similar to that illustrated in FIG. 1,showing a further form of the invention;

FIG. 11 is an enlarged broken sectional view of the structureillustrated in FIG. 10, taken on the line 11-11 thereof showing the finsin adjacent relation, and

FIG. 12 is an enlarged broken section-al view of the structuralillustrated in FIG. 10, taken on the line 12-12 thereof, showing thetins in spaced relation.

Description of the preferred embodiments A machine for practicing thepresent method is illustrated in FIGS. l to 8. The machine has centr-aluprights 11 and 12 and supporting posts 13` at each end. The post anduprights support a pair of guide rods 14 on which pulling devices 15 and118 and reversing devices 16 and 17 are slidably mounted on oppositesides of the uprights 11 and 12 respectively. The pulling devices 1'5and 18 are mounted on upright channels 19 which are supported oncarriages 21 and 22 having wheels 23 thereon which run upon a pair oftracks 24. A pair of cylinders 25 and 26 are supported between thetracks having piston rods 27 and 28 extending therefrom and connectedt-o plates 29 and 31 which are attached to the carriages 2-1 and 22.

The uprights 11 and 12 support a platform 32 on which a slide 33 ismounted for incremental movement. A tray 34 rests upon the slide 33 andabuts a pair of stop elements 35. A stack of fins 36 with end channels37 are mounted within the tray and accurately spaced from each other bycollars 38 about the apertures through the tins. The apertures arealigned forming a plurality of openings 39 through the stack whichextend above the end flanges 41 ofthe slide 33.

As illustrated more specifically in PIG. 7, the bottom of the tray has abar 42 attached thereto which mates with a slot 43 in the plaform 32.The bar 42 has teeth 44 extending downwardly therefrom actuated by apawl 45 carried by a head 46 on a piston rod 47 extending from acylinder 48 which is attached to the bottom of the platform 32. The pullheads and 18 have a clamping jaw 49, each of which is actuated by acylinder 51 to open and closed positions. When the jaws are in openposition the end of the tube may be swung away therefrom in a horizontalplane. The jaws 49 on the pull devices 15 and 18 are in aligned relationon the center of the machine which is indicated by a line 52 havingarrows at each end.

The reversing device 16 and 17 are illustrated in FIG. 4 as having ahead 53 mounted on the rods 14. The head 53 has a rotatable jaw 54carrying clamping fingers 55 which are pivotally mounted on a rod 56which is supported on a cross member 57 carried by the head 53 forrotative movement relative thereto. The jaw 54 is rotatably supported ona cross head 58 carried on a pair of rods 60 on a plate 61 which isattached to a piston rod 62 actuated by a ram 63 supported on a U-shapedbracket 64 attached to the head 53. The jaw 54 has a gear section 65with the teeth thereof in mesh with the teeth of a rack 66 actuated by apiston rod 67 from a cylinder 68. After the tube 59 has been drawnthrough an opening, the jaw 54 is raised to have the fingers 55 clampthe tube. Thereafter the rack 66 is operated to rotate the jaw and tubethrough 180. The head 53 has a pair of rods 71 slidably extendingtherethrough with nuts 50 on the forward end, the opposite end beingfixed to the pulling devices 15 and 18 The platform 32 has an extension72 at each side on which a loop forming mechanism 73 is supported. Thismechanism is illustrated more specifically in FIG. 3, wherein a U-shapedframe 74 has flange extensions 75 which project through slots 76 throughthe platform. The extensions are interconnected by a plate 77 to which acylinder 78 is secured. A cylinder 79 is mounted on the top web of theU-shaped element 74 having a piston rod 81 which supports a conicalelement 82 having an annular arcuate end 83. An element having a similararcuate end 84 is mounted on a piston rod 85 extending from the cylinder78. When the piston rods 81 and 85 are moved toward each other the twoarcuate ends 83 and 84 form an annular recess about which the loops isformed when one end of the tube is pulled through an opening through thestack of fins and end channel elements.

A ram 80 is supported on a frame 86 secured to the platform extension 72having a piston rod 87 which is attached to the U-shaped frame 74. Apredetermined pressure is provided for resisting the movement of theframe 74 after the tube is advanced around the abutted arcuate elements83 and 84. The frame 74 is drawn toward the slide 33 until the loop isdisposed adjacent to the slide. When the arcuate ends are separated theframe 74 retracts to permit the formed loop and slide to be advanced.Bearing plates 88 may be provided on the shoulders above the platformformed at the junction of the extensions 75. An arcuate shaped guide 90has a small end located adjacent to the arcuate ends 83 and 84 to directthe tube end into engagement therewith and into alignment with theopening. A hydraulic valve 91 is mounted on the pulling heads 15 and 18having a plate 92 on the end in position to be engaged by the tube 59after the tube has passed through the jaw 49.

The operation The stack of fins 36 and end elements 37 are disposed onthe tray 34 and delivered to the slide 33 in abutting relation to thestops 35. The slide had been retracted to have the first opening 93through the stack aligned with the centerline 52 and the jaws 49 of thepulling heads 15 and 18. The end of a length of tube 59 is advancedthrough the first opening 93 and into the jaws 49 of the pulling head15. When the end of the tube 59 strikes the plate 92, the valve 91 isactuated and the piston rod in the cylinder 51 moves forwardly to closethe jaw 49 which tightly grasps the end of the tube. Upon the closing ofthe jaw 49, a switch 95 is actuated to energize the valve for supplyingfluid to the right-hand end of the cylinder 26 to move the carriage 21to the left. This movement pulls the tube 59 through the opening 93leaving an end 96 extending from the right-hand channel element 37.During this movement the rods 14 are carried to the left by the head 15until the nuts 50 engage the reversing device 16 and move it to the leftalong with the head 15. The distance between the head and deviceprovides a length of tube which is required for inserting through thenext opening 97.

When the pressure on the fluid in the cylinder 26 rises to apredetermined amount as the carriage reaches the end of its travel limitby the pull on the tube 59, a valve is actuated to cut off the fluid tothe cylinder 26 and energize the ram 63. This raises the cross head 58and the jaw 54 which clamps the fingers 55 about the tube 59. Thiscauses a valve 98 to be operated to introduce fluid to the outer end ofthe cylinder 68 and advance the piston rod 67 and rack 66 to rotate thejaw 54 through 180 travel. As the jaw rotates, the end of the tube 59 ismoved out of the jaw 49 of the carriage 21 and the tube section isreversed and aligned with the centerline 52 and the jaws 49. Thereversing of the tube causes the turning device to be advanced by thepull on the other tube portion toward the platform 32 and energizes avalve which produces the indexing of the slide 33 and the location ofthe next opening 97 on the centerline 52. At the end of the turningoperation, a switch 99 is energized to operate a valve to produce thelowering of the cross head 58 and a flow of fluid to the front end ofthe cylinder 26 to thereby move the carriage 21 to the right which willpick up the turning device 16 and move it to the right to advance theend of the tube into the opening 97 from the left-hand side thereof.

The portion of the tube extending from the opening 93 is free to moveoutwardly as the end of the tube is advanced to and through the' opening97 and into the jaw 49 on the carriage 22 at the right-hand side of themachine. The striking of the plate 92 by the end of the tube energizesthe valve 91 and closes the jaw 49. This energizes the switch 95 whichoperates a valve to introduce fluid to the left-hand end of the cylinder25 and move the carriage 22 to the right. This movement will continueIuntil the loop is formed about the two arcuate elements 83 and 84 as theU-shaped frame 74 is moved toward the platform 32 to reduce the size ofa loop 101 formed on the left-hand side of the fin assembly. As thepressure mounts at the end of the stroke, a valve will be operated toshut off the fluid to the cylinder 25 and to supply fluid to the ram 63of the turning device 17 which is moved to the left. The' ram 63 movesthe crosshead 58 upwardly operating the valve 98 and advancing the rack66 to rotate the jaw 54 through 180. This operates the switch 99 whichreverses the flow of fluid to the cylinder 25 and causes the carriage 22and head 18 to move to the left engaging the reversing device 17. Thisproduces the lowering of the crosshead 58 and moves the reversingdevice.I toward the platform 32 feeding the tube length through the nextopening 102 until the end is passed through the jaw 49 on the carriage21 and clamped therein.

When the frame 74 reaches the end of its travel it operates a valve (notshown) to reverse the flow of fluid to the lcylinders 78 and 79 andthereby separate the two arcuate elements 83 and 84 to permit the frame74 to retract and the slide 33 to be indexed one step to align the nextopening 103 with the centerline 52. The operation continues in thismanner of reversing a section of the tube and pushing the end through anopening, clamping the end and pulling the remainder of the tube throughthe opening and forming alternate loops 101 at the ends of the iinstack. After the tube 59 has been inserted through the last opening 104the tube is expanded and the ends are cut to leave a short sectionextending at each side to which a short copper tube (not shown) isbrazed, welded or otherwise secured when the tube 59 is made from amaterial diicult to braze. The ends formed by the copper tube can beeasily attached to conduits in a heat exchange system.

By the use of the machine, the conducting tube is threaded back andforth through openings formed by aligned apertures through the fins withoppositely disposed loops formed at the ends of the straight portionswhich are expanded by pressure, mechanical means or otherwise to havethe fins and straight portions of the tubes in conducting relation toeach other. A pressure uid may be employed to produce the expansion byattaching the pressure line to the conduit 96 and closing the other endof the tube. A ball with a piston therebehind may be' traversed throughthe tube by pressure or pulled by a cable to produce the mechanicalexpansion of the tube wall. The latter machine and method isillustrated, described and claimed in applicants co-pending application,Ser. No. 702,490, filed Jan. 15, 1968, for Machine and Method ofExpanding Tube Sections which was assigned to the assignee of thepresent invention. It is to be understood that the machine can beforeshortened by rst inserting the tube through the cenral opening 103and threading one end through the openings located on one side thereofin the manner pointed out above, and thereafter threading the other endthrough the openings located on the other side thereof.

When the tube is made of a hard material which makes it difficult tohave it drawn forwardly about the arcuate elements 83 and 84, the methodof FIG. 9 can be practiced. This embodies the use of two half-arcuateelements 106 disposed adjacent to the end channels 37 with a guideelement 107 adjacent thereto for guiding thevfree end of the tubethrough an opening as the loop 108, shown in dot dash line, is reducedin size about the abutted elements 106 to form the loop 101 in finalposition. This is made possible by supporting the cylinder 79 on theoverhanging end of a plate 109 supported on one or more xed uprights110, as illustrated in FIG. 10, so that when the loop 101 is released bythe separation of the half elements 106, the slide 33 can be indexed.After the two halves 106 have been separated by the movement of thepiston rods 81 and 8S into the cylinders 79 and 78 the slide 33 isindexed to have the next opening aligned on the centerline 52.

A further method of constructing the heat exchanger is illustrated inFIGS. to 12 wherein the stack is composed of tins 111 which are plainstrips 'with apertures therethrough alternately disposed with spreadingcombs 112 and with end plates 113 at the ends of the stack. The

stack is disposed in a flanged tray 114 which is supportedk in a slide110 located between plates 115. The combs 112 are made of hard springsteel having aligned straight portions 116 and 117 and an arcuateportion 118 therebetween. A pair of apertures 119 are provided in thestraight portion 117 of the combs 112 through which a pair of rods 121extend. The rods are secured in a rectangular frame 122 which issupported on theI tray by posts 123. A tube 124 is threaded back andforth through the opening in the tins and end plates and looped aboutthe half arcuate elements 106 with the assembly indexed after each loopis formed. Thereafter the assembly is advanced to have the loops extendover bars 125 which are supported on posts 126 on a plate and ram whichraises the bars 125, the loops and straight portions. When this occurs,the fins and end plates pass over the arcuate sections 118 of the combs112 and are spread apart, as illustrated in FIGS. 10 and 12. The tins111 are evenly spaced on the straight tube portions with the end plates113 contacting the loops at the ends of the half circle for-1n thereof.A fluid delivery plug 127 and sealing plug 128 are advanced to engagethe ends 129 of the tube to pressurize the internal area of the tube bya delivered fluid which expands the tube into conducting relation withthe edges of the iin apertures providing 360 contact therebetween. Thisengagement maintains the fins, the end plates and tube in xed relationto each other. The expansion can be performed by other means and theconducting relationship can also be produced by brazing and the like.

It has been herein illustrated how the tube may be threaded back andforth through the openings in a stack of tins and end plates. The methodembodies the formation of loops at each side of the stack. from acontinuous tube having straight portions extending through the openingsthrough theI stack. When there are two rows of openings the slide may bedisposed at an angle so that the tube can be threaded from one row ofopenings to the next row to form the loops in a horizontal plane. Anyposition of loops may be formed from the tube to provide the desiredpath for the fluid to be cooled or heated. Several heat exchangers maybeI made continuously and stacked one upon the other by the twisting ofthe loop joining the different exchanger units. In any event the methodprovides the formation of a single row of tubes or any multiplicitythereof employing a single tube which is continuous. The method islimited only lby the practical length of the tube which can be handledby the machine starting from the end or the center of the stack of ns.

What is claimed is:

1. The method of constructing a heat exchanger which includes the stepsof stacking a plurality of spaced metal tins, each 1in having aplurality of apertures, with the apertures therethrough aligned to forma plurality of openings, and threading a metal tube back and forththrough the openings to provide a continuous uniform passageway, saidback and forth threading forming reverse bends of the tube at the endsof the iin stack.

2. The method as recited in claim 1, wherein the tube portions withinthe openings are conductively joined to the fins.

3. The method as recited in claim 1, wherein the tube portions withinthe openings are expanded to engage the entire rim of the apertures ofthe fins.

4. The method as recited in claim 1, wherein the threading of the tubeproduces straight portions extending through said openings and whereinthe bending of the tube back and forth during the threading operationproduces oppositely presenting loops at the ends of the straightportions at opposite ends of the iin sta-ck.

4 5. The method as recited in claim 1, wherein the ns are spaced apredetermined distance apart by collars about the aperturestherethrough.

6. The method as recited in claim 1, wherein reinforcing elements areplaced at the ends of the ns having apertures aligned with said openingsand through which the tube is inserted during the threading operation.

7. The method as recited in claim 4, wherein the loops and tins aremoved relative to each other to space the fins relative to the loops.

8. The method as recited in yclaim 1, wherein the fins are stacked withspreading combs therebetween which move the tins toward the loops andspace them relative to each other upon the relative movement between thecombs and tins.

9. The method of constructing a heat exchanger which includes the stepsof: aligning apertures through the body of a stack of metal tins, eachiin having a plurality of apertures, to provide a plurality of spacedopenings; threading a continuous length of metal tubing back and forththrough said openings with straight portions extending through the ns,and forming loops of the tubing at 2,462,511 the ends of the straightportions between each back and 2,494,548 forth threading thereof.2,747,258

10. The method as recited in claim 9, wherein a con- 2,941,569 ductingrelationship is produced between the surface Of 3,140,533

the tube and the entire rim of the fin apertures. 5

References Cited UNITED STATES PATENTS Kramer 165-151 X Goldberg 165-151Kramer 29-157.3 Holt et al 29-202 X Ronbeck.

JOHN F. CAMPBELL, Primary Examiner.

D. C. REILEY, Assistant Examiner.

U.S. Cl. X.R.

